There have been so many episodes, it's actually kind of hard for me to think of them chronologically. It's rare that an episode goes by without at least one or two lines that make me laugh out loud. I don't know if this episode has aired overseas yet, but around Christmas there was an excellent new holiday Simpsons, with brief parodies of many different various children's Christmas programs. There were even two brief stop-motion animated sequences, parodying the Rankin-Bass 'Rudolph' shows.
One of my favorite bits of Simpsons dialog was from many seasons back. (Incidentally sysops: this dialog was broadcast on American TV, often regarded as extremely prudish language-wise, so I'm assuming I'm not breaking any rules posting it here.)
BART: Homer, I gotta say, your half-assed over-parenting is even worse than your half-assed under-parenting was!
HOMER: But I'm using my whole ass!